The girl, whose name has not been released by CBP, and her father were apprehended after crossing the border illegally into New Mexico with her family and over 160 other migrants. Medical personnel are not staffed in the remote area where they were held, known as Antelope Wells, the officials said.

Before the group left Antelope Wells by bus to be transferred to a border station, her father reported that she was ill and vomiting. By the time she arrived at the border station an hour-and-a-half later, she was not breathing. She was revived twice by emergency workers and then transported by air to a hospital in El Paso, Texas, where she died of cardiac arrest with her father by her side.

She was severely dehydrated; however, officials say that migrants were given access to water at Antelope Wells.

A spokesperson for the Department of Homeland Security said, "Unfortunately, despite our best efforts and the best efforts of the medical team treating the child, we were unable to stop this tragedy from occurring."

The incident raises questions about CBP's emergency procedures and the Trump administration's policy of delaying immigrants at legal ports of entry, forcing them to decide between waiting for weeks to months in dangerous border towns or traveling through dangerous areas along the border.

CBP Commissioner Kevin McAleenan testified before Congress on Tuesday that the border stations were not built to handle children. In November, over 25,000 immigrants crossed as part of a family with children and over 5,200 children crossed without a guardian.

"Our infrastructure is incompatible with this reality. Our border patrol stations and ports of entry were built to mostly handle male single adults in custody. Not families or children," said McAleenan.

Officials on Friday could not say whether McAleenan knew of this death before his testimony to the Senate Judiciary Committee.

Immigration advocates have criticized the Trump administration for not properly staffing ports of entry to process asylum claims from immigrants who cross legally and for not doing enough to address the humanitarian concerns of immigrants who make dangerous journey between legal ports of entry.

The humanitarian group No More Deaths has posted videos of border agents have destroyed the gallons of water their volunteers leave in the desert for dehydrated migrants.